JPH06145979A - Film forming device - Google Patents

Abstract

PURPOSE:To change the acceleration energy of the ions with which a base body on a holder is irradiated over a wide range by applying a positive or negative bias voltage to this base body. CONSTITUTION:This film forming device has an evaporating source 8 which deposits a material constituting the film by evaporation on the base body 6 and ion source 12 with which the base body is irradiated with ion 14. The positive or negative bias voltage is applied from a DC bias power source 20 to the base body 6 (if the base body is conductive) or the holder 4 (if the base body is nonconductive) between the holder 4 of the base body 6 and the ground. The energy with which the base body 6 is irradiated is controlled by controlling the bias voltage to be applied to the base body 6 or the holder 4 even if the accelaration energy of ions 14 to be drawn out of the ion source 12 is not changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in the manufacture of tools, sliding parts, electric circuit boards, electronic circuit elements, etc., where a film is formed on the surface of a substrate by a combination of vapor deposition and ion irradiation. The present invention relates to a film forming apparatus for forming.

[0002]

2. Description of the Related Art A combination of vapor deposition and ion irradiation is used for improving wear resistance and slidability of tools, improving thermal conductivity of electric circuit boards, and forming electronic circuit elements having semiconductor characteristics. Various films are formed on the surface of a substrate by the method.

FIG. 2 shows a conventional example of a film forming apparatus used for forming such a film. The film forming apparatus includes a vacuum container 2 that is evacuated by a vacuum exhaust device (not shown), a holder 4 that is provided in the vacuum container 2 and holds a substrate 6 on which a film is to be formed, and a substrate on the holder 4. 6, an evaporation source 8 for depositing a substance 10 that forms a film, and an ion source 1 for irradiating a substrate 6 on the holder 4 with ions 14.
2 and.

When the substance 10 constituting the film from the evaporation source 8 is vapor-deposited on the substrate 6, at the same time, alternately or after vapor deposition,
By irradiating the ions 14 from the ion source 12, a film made of the substance 10 constituting the film or a compound of the substance 10 and the ions 14 can be formed on the surface of the substrate 6.

According to such a film forming apparatus, there is an advantage that the irradiation ions 14 make the vapor deposition atoms highly excited, and the film structure which is a high temperature / high pressure phase can be synthesized at a low temperature. Further, the collision between the irradiation ions 14 and the vapor-deposited atoms pushes the vapor-deposited atoms into the surface portion of the substrate 6, and as a result, a mixed layer composed of the constituent materials of both is formed at the interface between the substrate 6 and the film thereon. However, since this acts like a wedge, there is also an advantage that the adhesion of the film to the substrate 6 is significantly improved.

[0006]

In the film formation by the film forming apparatus as described above, the characteristics of the film are largely changed by the acceleration energy of the irradiated ions 14, and for example, the energy of the irradiated ions 14 is changed. A larger value improves the adhesion of the film, and a smaller acceleration energy of the ions 14 improves the crystallinity of the film.

Since the crystallinity of the film correlates with the hardness and insulating property of the film, for example, the acceleration energy of the ions 14 irradiating the substrate 6 is increased at the initial stage of forming the film, and then the substrate 6 is first formed.
A film forming method for improving the crystallinity of the film by improving the adhesion between the film and the film, and subsequently, as the film is formed, the acceleration energy of the ions 14 irradiating the substrate 6 is reduced to improve the crystallinity of the film. It is selected depending on the type.

In order to realize such a film forming method,
It is not sufficient to simply change the acceleration voltage in the ion source 12, and the acceleration energy of the ions 14 can be changed over a wide range from a small value to a large value (for example, about 100 eV to 40 KeV). Special ingenuity is required.

That is, in the extraction electrode system of the ion source, the plasma electrode (the electrode having a positive potential) and the suppression electrode (the electrode having a negative potential) on the downstream side thereof, or the ground electrode (the potential is set to the ground potential) when there is no such electrode. Electrode), the distance between
Letting V be the acceleration voltage applied to the plasma electrode and I be the current amount of the extracted ions, I = K · V ^3/2 / d ² (K is a constant) (1) holds, and the acceleration energy of the ions If the accelerating voltage V is simply changed in order to change, the current amount I of the extracted ions will also change. Therefore, even if the ion acceleration energy is changed, in order to keep the ion current amount as constant as possible and keep the processing rate constant, it is necessary to adjust the electrode spacing d to match the ion acceleration energy.

However, it is difficult to adjust the distance between the electrodes of the ion source from the outside of the vacuum container, and there are many difficult points such as a very complicated structure. Therefore, when acceleration energy over a wide range is required, Generally, a plurality of ion sources having different electrode intervals, that is, different acceleration energies are used. For example, in the apparatus shown in FIG. 2, an ion source 16 is further provided in addition to the ion source 12 to extract low-energy ions 14 of, for example, 2 KeV or less from one of the ion sources 12 and, for example, 2 from the other ion source 16.
The ions 18 having high energy of KeV or higher are extracted.

However, in an apparatus provided with a plurality of ion sources having different accelerating energies, the number of ion sources and power supplies for the apparatus is increased, so that the configuration of the apparatus becomes very complicated and the cost also increases significantly. There is.

Therefore, it is a primary object of the present invention to provide a film forming apparatus capable of changing the acceleration energy of ions with which a substrate is irradiated in a wide range with a simple structure.

[0013]

In order to achieve the above object, the film forming apparatus of the present invention is a DC bias power supply for applying a positive or negative bias voltage to a substrate on a holder or a holder as described above. Is provided.

[0014]

According to the above structure, the energy of the ions irradiated on the substrate can be controlled by controlling the bias voltage applied to the substrate or the holder without changing the acceleration energy of the ions extracted from the ion source. it can. More specifically, by setting the above bias voltage to a positive bias voltage, the ions extracted from the ion source are decelerated by this bias voltage, so that the bias voltage is accelerated by the amount of the bias voltage. Energy becomes small. On the contrary, by setting the bias voltage to a negative bias voltage, the ions extracted from the ion source are further accelerated by this bias voltage, and the acceleration energy of the ions irradiated on the substrate is as much as the bias voltage. growing.

In this way, the energy of the ions irradiated to the substrate can be varied over a wide range with a simple structure without using an ion source having a complicated structure or using a plurality of ion sources and a power source for it. be able to.

[0016]

1 is a schematic sectional view showing a film forming apparatus according to an embodiment of the present invention. The same or corresponding portions as those of the conventional example in FIG. 2 are denoted by the same reference numerals, and the differences from the conventional example will be mainly described below.

In this embodiment, between the holder 4 and the ground as described above, on the base 6 on the holder 4 (when the base 6 is conductive) or on the holder 4 (when the base 6 is non-conductive). A direct-current bias power source 20 for applying a positive or negative bias voltage is connected thereto.

By providing such a bias power source 20, the substrate 6 is irradiated by controlling the bias voltage applied to the substrate 6 or the holder 4 without changing the acceleration energy of the ions 14 extracted from the ion source 12. It is possible to control the energy of the ions 14 that are ejected. More specifically, by setting the bias voltage output from the bias power source 20 to a positive bias voltage, the ions 14 extracted from the ion source 12 are decelerated by this bias voltage, so that the bias voltage is as much as the substrate. The accelerating energy of the ions 14 radiated to 6 becomes small. On the contrary, by setting the bias voltage output from the bias power source 20 to a negative bias voltage, the ions 14 extracted from the ion source 12 are further accelerated by this bias voltage. The acceleration energy of the irradiated ions 14 becomes large.

Moreover, it is easy to control the bias voltage over a wide range, and thus the acceleration energy of the ions 14 with which the substrate 6 is irradiated can be controlled over a wide range as described above.

Therefore, even when it is necessary to change the acceleration energy of the ions 14 applied to the substrate 6 over a wide range, a complicated ion source having a structure corresponding to the wide range of acceleration energy and a power source therefor are not used. Or a plurality of ion sources having different acceleration energies and a power source for them are not used, and only the bias power source 20 needs to be added, so that the configuration of the apparatus becomes very simple. Further, along with this, the cost of the device can be significantly reduced.

Moreover, since the acceleration energy of the ions 14 applied to the substrate 6 can be freely changed from large to small by the bias voltage applied to the substrate 6 and the like, the ion source 12 and the power source therefor are small. It only needs to support acceleration energy, and for this reason also the cost of the device can be significantly reduced.

More specifically, a cubic crystal is formed on the surface of a metal substrate such as cemented carbide (WC) by using vapor deposition of boron and irradiation of nitrogen ions in combination with an apparatus as shown in FIG. When forming a boron nitride film containing boron nitride (c-BN), nitrogen ions require an acceleration energy of 10 KeV or more in order to form the boron nitride film on a metal substrate with good adhesion, and the film crystal Improves c
In order to obtain a high-hardness boron nitride film containing a large amount of -BN, it is preferable to use nitrogen ions having an acceleration energy of 1 KeV or less.

In such a case, according to the film forming apparatus, only one ion source 12 and a power source for the ion source 12 corresponding to an acceleration energy of 1 KeV or less are prepared,
Further, as the bias power source 20, a power source capable of outputting a negative bias voltage of 9 KV or more in absolute value may be prepared.

With such a structure, in the initial stage of forming the boron nitride film, the ions 14 having an acceleration energy of 1 KeV or less are extracted from the ion source 12 and irradiated onto the substrate 6, and at the same time, the substrate 6 and A bias voltage of −9 KV is applied from the bias power source 20 to the holder 4,
Then, application of the bias voltage can be stopped during the film formation, and the base 6 can be irradiated with the ions 14 with the acceleration energy when extracted from the ion source 12.

In such a case, conventionally, for example, both an ion source corresponding to low energy (for example, 2 KeV or less) and an ion source corresponding to high energy (for example, 2 KeV or more) are required, and they are compatible. Since each power source is also required, the structure becomes complicated and the cost increases.

When the acceleration energy of the ions 14 with which the substrate 6 is irradiated is changed continuously or intermittently,
If this is done by the ion source, the current amount of the extracted ions changes as described in the above formula (1). Therefore, when film formation must be performed at a constant ion current, the ion current Adjustment is necessary and takes a lot of time.
On the other hand, according to the film forming apparatus, even if the bias voltage applied to the substrate 6 or the like is changed, only the acceleration energy of the ions 14 with which the substrate 6 is irradiated is changed and the current amount of the ions 14 is changed. Since it does not change itself, it is not necessary to adjust the ion current each time, and therefore the productivity of film formation can be improved.

The evaporation source 8 used in the film forming apparatus of this embodiment is not limited to a specific type, and for example, the evaporation material is heated by electron beam heating, resistance heating, high frequency heating, or the like. The substance 10 forming the film may be evaporated by vaporization, or the substance 10 forming the film may be deposited by sputtering the target.

Also, the ion source 12 is not limited to a particular type, and for example, a Kauffman type ion source for confining thermoelectrons generated from a filament (cathode) by an external magnetic field in the axial direction of the anode, or the same heat source. A bucket type ion source or the like for confining electrons by a multipolar magnetic field is appropriately used.

Ions 1 extracted from the ion source 12
4 may be a compound film formed by combining with the substance 10 forming the film, or may be an inert gas ion.

The angle of incidence of the ions 14 on the substrate 6 is not limited to a particular angle, and the film may be formed while rotating the substrate 6 as necessary.

[0031]

As described above, according to the present invention, since a direct current bias power source for applying a positive or negative bias voltage to the substrate on the holder or the holder is provided, an ion source having a complicated structure is used. The acceleration energy of the ions with which the substrate is irradiated can be varied over a wide range with a simple configuration without using a plurality of ion sources and a power source for the ion sources. Therefore, the cost of the device can be significantly reduced.

Moreover, even if the acceleration energy of the ions irradiated to the substrate is changed continuously or intermittently, the amount of current of the ions irradiated to the substrate does not change, so that film formation is performed with a constant ion current. Even in such a case, it is not necessary to adjust the ion current every time the ion acceleration energy is changed, and therefore the productivity of film formation can be improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an example of a conventional film forming apparatus.

[Explanation of symbols]

 2 vacuum container 4 holder 6 substrate 8 evaporation source 10 substance constituting film 12 ion source 14 ion 20 bias power source

Front page continuation (72) Inventor Akinori Ebe 47 Umezu Takaune-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture Nissin Electric Co., Ltd.

Claims (1)

[Claims] 1. A vacuum container, a holder provided in the vacuum container for holding a substrate on which a film is to be formed, an evaporation source for depositing a substance forming a film on the substrate on the holder, and the same. In a film forming apparatus including an ion source for irradiating a substrate on a holder with ions, a DC bias power source for applying a positive or negative bias voltage to the substrate on the holder or the holder is provided. Film forming apparatus.